Many service providers are interested in operating MPLS-TP (MultiProtocol Label Switching-Transport Profile) in ring topologies. MPLS ring topologies offer many advantages, including that they can be used with any underlying transport technology. However, service providers require a high level of survivability in the event of a network link failure. Such a network link failure may be a complete failure of a network link caused for example, where the network links comprise optical fibres, by an optical fibre cut or defect. Alternatively, the network link failure may be a failure of the network link to transport traffic at a desired performance level.
A way of providing restoration of an MPLS ring network in the event of a network link failure has been proposed to the Internet Engineering Task Force (IETF) standards body. The proposed system requires four Label Switched Paths (LSPs), which may also be referred to as “tunnels”, to be set up for each traffic ingress/traffic egress node pair in the ring: a working LSP in the clockwise direction, a working LSP in the anticlockwise direction, a restoration LSP in the clockwise direction (which may also be referred to as a protection LSP) and a restoration LSP in the anticlockwise direction. FIG. 1 illustrates these LSPs 14 for one traffic ingress/egress node pair in an MPLS ring network 10. However, it will be appreciated that an MPLS ring network 10 will typically comprise several ingress/egress node pairs. Therefore many multiples of four LSPs may be required in order to provide protection for each of these connections. Thus, the proposed system may require a large number of LSP labels, which would create a heavy load on the management system. Furthermore, the proposed system operates such that, when a network link failure occurs, traffic may be doubled back or “wrapped” from a network node adjacent the network link failure. Thus, some traffic may traverse a network section twice, wasting network bandwidth.